第4部分：阅读理解(第31-45题，每题3分，共45分)

　　下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。

　　第一篇

Walking to Exercise the Brain

　　Do you think sitting and studying all the time will improve your grades?Think again．Getting some exercise may help，too．

　　New research with older people suggests that taking regular walks helps them pay attention better than if they didn't exercise．

　　Previous research had shown that mice learn，remember，and pay attention better after a few weeks of working out on a running wheel．Mice that exercise have greater blood flow to the brain than those who don't．Their brain cells also make more connections．

　　Neuroscientists from the University at Urbana-Champaign wanted to find out if the same thing is true for people．First，they measured the physical fitness of 41 adults，ages 58 to 77，after each per-son walked 1 mile．Then，participants looked at arrows on a computer sczeen and had to use com-puter keys to show which way one particular arrow was pointing．

　　Adults who were physically fit were faster at the arrow task，and their answers were just as ac- curate as their less-fit peers,the researchers found．The fitter participants also had more blood flow to a part of their brain responsible for paying attention and making decisions．

　　In a second study，15 elderly people who completed a 6-month aerobic-training course were fas-ter at attention tasks compared with 14 seniors who just did stretching and toning exercises for the same amount of time．

　　So，even going for a walk every 2 or 3 days forjust 10 to 45 minutes can help．That should be good news for your grandparents．

　　The effects of exercising on the brains of younger people haven't been studied yet．Still，it can't hurt to take occasional study breaks and go for a walk or run around with your friends．You might even do better in school．

　　Whatever you do，though，don't try to read and walk at the same time．You could end up hurting yourseff!

　　31．Walking regularly helps elderly people_______．

　　A．lose weight

　　B．become happier

　　C．concentrate better

　　D．look younger

　　32．After taking exercise for a few weeks，the mice were found to have_____．

　　A．higher blood pressure

　　B．faster heartbeat

　　C．more blood flow to the brain

　　D．better appearance

　　33．The first study on 41 elderly people found______．

　　A．the less-fit participants did arrow tasks faster

　　B．the fitter participants did arrow tasks faster

　　C．the less-fit participants gave more accurate answers

　　D．the fitter participants gave more accurate answers

　　34．It can be good for health when one takes a walk every 2 or 3 days for at least______．

　　A．3 minutes

　　B．45 minutes

　　C．30 minutes

　　D．10 minutes

　　35．It is suggested in the last paragraph that people should______．

　　A．run around once a week

　　B．not read and walk at the same time

　　C．go for a walk every day

　　D．not hurt their friends while exercising

　　第二篇

Night of the Living Ants

　　When an ant dies，other ants move the dead insect out of the nest．This behavior is interesting to scientists，who wonder how ants know for sure and so soon that another ant is dead．

　　Dong-Hwan Choe，a scientist at the University of California found that Argentine ants have a chemical on the outside of their bodies that signals to other ants．"I'm dead．take me away．"

　　But there's a twist to Choe's discovery．These ants ave a little bit like zombies(僵尸)．Choe says that the living ants，not just the dead ones，have this death chemicals．In other words．While an ant crawls around，perhaps in a picnic or home，it's telling other ants that it's dead．

　　What keeps ants from hauling away the liring dead?Choe found that Argentine ants have two additional chemicals on their bodies，and these tell nearby ants something like，"Wait-I'm not dead yet，"So Choe's research turned up two sets of chemical signals in ants：one says，"I'm dead．"the other set says，"I'm not dead yet．"

　　Other scientists have tried to figure out how ants know when another ant is dead． If an ant is knocked unconscious，other ants leave it alone until it wakes up．That means ants know that unmoving ants can still be alive．

　　Choe suspects that when an Argentine ant dies，the chemical that says"Wait-I'm not dead yet" quickly goes away.Once that chemical is gone，only the one that says"I'm dead"is left．"It's because the dead ant no longer smells like a living ant that it gets carried to the graveyard(墓地)，not because its body releases new unique chemicals after death，"said Choe． When other ants detect the"dead"chemical without the"not dead yet"chemical，they haul away the body． This was choe's hypothesis(假设)．

　　To test his hypothesis，Choe and his team put different chemicals on Argentine ant pupae(蛹). When the scientists used the"I'm dead"chemical，other ants quickly hauled tbe treated pupae away. When the scientists used the"Wait-I'm not dead yet"chemicals，other ants left the treated pupae alone.Choe believes this behavior shows that the"not dead yet"chemicals override(优先于) the"dead"chemical when picked up by adult ants． And that when an ant dies，the"not dead yet"chemicals fade away．Other nearby ants then detect the remaining"dead"chemical and remove the body from the nest．

　　36．What is meant by"death chemical"mentioned in paragraph 3?

　　A．A chemical that contains poison．

　　B．A chemical that causes death．

　　C．A chemical that announces death．

　　D．A chemical that prevents death．

　　37．Which of the following statements is NOT true of ants?

　　A．Ants know very soon that another ant is dead．

　　B．When an ant is dead，others move its body out of the nest．

　　C．If an ant is unconscious，it is moved out of the nest．

　　D．Living ants have the"I'm dead"chemical on their bodies．

　　38．According to Choe's hypothesis，___________.

　　A．an ant still smells like a living when it dies

　　B．the"I am dead"chemical leaves the ant's body when it dies

　　C．the"I am not dead yet"chemical is left when an ant dies

　　D．the"I am not dead yet"chemical leaves the ant's body when it dies

　　39．According to paragraph 7，what is the result of the test on Choe's hyothesis?

　　A．It shows that his hypothesis is wrong．

　　B．It proves that his hypothesis is convincing．

　　C．It suggests that his hypothesis needs revising．

　　D．Not enough evidence has been found to support his hypothesis．

　　40．The passage"Night of the Living Ants"tells us about________.

　　A．how an ant is moved out of the nest at nigh

　　B．what an ant does at night

　　C．how an ant finds its way in darkness

　　D．what happens when an ant dies

　　第三篇

The Iceman

　　On a September day in 1991，two Germans were climbing the mountain between Austria and Italy．High up on a mountain pass，they found the body of a man lying on the ice. At that height (10,499 feet or 3，200 meters)，the ice is usually permanent，but 1991 had been an especially warm year．The mountain ice had melted more than just usual and so the body had come to the surface．

　　It was lying face downward．The skeleton(骨架)was in perfect condition，except for a wound in the head．There was still skin on the bones and the remains of some clothes．The hands were still holding the wooden handle of an ax and on the feet there were very simple leather and cloth boots．Nearby was a pair of gloves made of tree bark(树皮)and a holder for arrows．

　　Who was the man? How and when had he died? Everybody had a different answer to these questions．Some people thought that it was from this century，perhaps the body of a soldier who died in World War I．since several soldiers had already been found in the area． A Swiss woman who believed it might be her father, who had died in those mountains twenty years before and whose body had never been found．The scientists who rushed to look at the body thought it was probably much older，maybe even a thousand years old．

　　With modern dating techniques，the scientists soon learned that the iceman was about 5，300 years old．Born in about 3300 B．C．，he lived during the Bronze Age in Europe．At first scientists thought he was probably a hunter who had died from an accident in the high mountains. More recent evidence．however，tells a different story．A new kind of X-ray shows an arrowhead still stuck in his shoulder．It left only a tiny hole in his skin，but it caused internal damage and bleeding．He almost certainlv died from this wound，and not from the wound on the back of his head．This means that he was probably in some kind of battle．It may have been part of a large war，or he may have been fighting bandits．He may even have been a bandit himself．

　　By studying his clothes and tools，scientists have already learned a great deal from the Iceman about the times he lived in．we may never know the full story of how he died，but he has given us important clues to the history of those distant times．

　　41．The body of the iceman was found in the mountains mainly because__________．

　　A．two Germans were climbing mountains

　　B．he was just on a mountain pass

　　C．the melted ice made him visible

　　D．he was lying on the ice

　　42．What can be inferred from paragraph 2?

　　A．The iceman could have died from the wound in the head．

　　B．The iceman was struck dead from behind．

　　C．The iceman was killed while working．

　　D．The iceman lived a poor life．

　　43．All the following are assumptions once made about iceman EXCEPT____________．

　　A．he was a soldier in Worid War I

　　B．he came from Italy

　　C．he was a Swiss woman'S long-lost father

　　D．He was born about a thousand years ago

　　44．The scientists made the deduction that the iceman_________．

　　A．was hit in the shoulder by an arrowhead

　　B．has a tiny hole in his skin causing his death

　　C．was probably in some kind of a battle

　　D．had got a wound on the back of his head

　　45．The word"bandits"in paragraph 4 could be best replaced by_________．

　　A．robbers

　　B．shooters

　　C．soldiers

　　D．hunters

　　同时按下Crtl键和A键查看答案
第一篇
31．C 32．C 33．B 34．D 35．B 
第二篇
36．C 37．C 38．D 39．B 40．D
第三篇
41．C 42．A 43．B 44．C 45．A

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